This invention relates to an emergency alarm system which utilizes one or more ion chamber smoke detectors for indicating the presence of smoke within a protected facility.
The present-day smoke detecting systems are typically in the form of individual units which are positioned at appropriate places throughout a building or other such facility which is to be protected. Wiring specifically for the alarm system is required which is oftentimes consuming and expensive. Such wiring often necessitates the partial remodeling of the building being protected. The present invention permits a building owner to use existing telephone wiring or other communications channels or power lines to carry alarm signals. Further, if communications channels are not already present within the facility being protected, a telemetry system is provided which generates radio signals which can be transmitted from the smoke detector to a centralized responder unit so that immediate detection of a potential fire can be effected. An important feature of the subject invention is a continuous testing system wherein periodic signals of predetermined time duration are transmitted from the individual smoke detector units to the central responder unit via the communications lines or radio waves. When an individual smoke detector undergoes a fault condition, the test signals are interrupted, thereby causing a slave timer at the responder unit to generate a signal which energizes a fault indicator. Accordingly, by the smoke detector system of the present invention, a fail-safe detector unit is provided for measuring and detecting smoke emissions within a facility being protected.